Exogenous Nitric Oxide (NO) Interferes with Lead (Pb)-Induced Toxicity by Detoxifying Reactive Oxygen Species in Hydroponically Grown Wheat (Triticum aestivum) Roots.

Gurpreet Kaur,Ravinder Kumar Kohli,Harminder Pal Singh,Daizy R Batish,Valbha Rishi,Priyanka Mahajan,Zhulong Chan

doi:10.1371/journal.pone.0138713

Gurpreet Kaur, Ravinder Kumar Kohli + Show 5 more

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https://doi.org/10.1371/journal.pone.0138713

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Journal: PloS one	Publication Date: Sep 24, 2015
Citations: 80	License type: CC BY 4.0

Affiliation: Panjab University, Punjab Engineering College

Abstract

Nitric Oxide (NO) is a bioactive signaling molecule that mediates a variety of biotic and abiotic stresses. The present study investigated the role of NO (as SNP [sodium nitroprusside]) in ameliorating lead (Pb)-toxicity in Triticum aestivum (wheat) roots. Pb (50 and 250 μM) alone and in combination with SNP (100 μM) was given to hydroponically grown wheat roots for a period of 0–8 h. NO supplementation reduced the accumulation of oxidative stress markers (malondialdehyde, conjugated dienes, hydroxyl ions and superoxide anion) and decreased the antioxidant enzyme activity in wheat roots particularly up to 6 h, thereby suggesting its role as an antioxidant. NO ameliorated Pb-induced membrane damage in wheat roots as evidenced by decreased ion-leakage and in situ histochemical localization. Pb-exposure significantly decreased in vivo NO level. The study concludes that exogenous NO partially ameliorates Pb-toxicity, but could not restore the plant growth on prolonged Pb-exposure.

Highlights

Various anthropogenic activities, such as disposal of sewage sludge and electronic waste, mining and smelting have resulted in augmentation of heavy metals in the natural environment [1]
Plumule growth was less sensitive to the toxic effects of Pb, with ~17% (50 μM) and 45% (250 μM) reduction relative to the control (Table 1)
Compared with Pb treatment alone, Nitric Oxide (NO) addition caused a significant decrease in MDA levels during 2–8 h of treatment

Summary

Introduction

Various anthropogenic activities, such as disposal of sewage sludge and electronic waste, mining and smelting have resulted in augmentation of heavy metals in the natural environment [1]. Upon accumulation in the soil, heavy metals may disturb soil biology and ecology; thereby inhibiting plant growth, affecting crop produce and even causing plant death [1, 2]. The phytotoxic effects of heavy metals have been attributed to pro-oxidative effects of metal ions, that disrupt various physiological and biochemical processes [2]. Lead (Pb) has been reported to induce reactive oxygen species (ROS) generation and alter enzymatic machinery in lupin roots, pea root cells, rice plants, maize roots, and aquatic plants such as Wolffia arrhiza and Elodea canadensis [3].

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